Vascular occlusions are now commonly diagnosed and treated by nonsurgical procedures. Coronary artery disease, for example, is a disease resulting in the full or partial occlusion of a coronary artery and is frequently treated by a nonsurgical procedure called percutaneous translumenal coronary angioplasty (PTCA). Peripheral translumenal angioplasty (PTA) is a similar nonsurgical procedure used to provide therapy to occlusions in the peripheral arteries. Other nonsurgical translumenal procedures such as atherectomy and laser ablation can be implemented to provide therapy to vascular occlusions occurring in the coronary arteries, peripheral arteries, cerebral arteries, and several other vascular sites.
Most nonsurgical translumenal procedures require the use of some type of guide member because the access point and the therapy site are a significant distance apart. The guide member can be used to guide a therapeutic device from the access point and along a vascular path leading to the site where therapy is to be provided.
Vascular paths are often long and tortuous and are thus sometimes difficult to navigate. Furthermore, vascular occlusions can be difficult to cross with a guide member due to the restricted through lumen. Vascular occlusions also inhibit fluid flow and thus the vascular path adjacent to and distal to the occlusion are difficult or impossible to visualize clearly with contrast media injections. The need to use guide members for nonsurgical translumenal procedures in combination with the difficulties in navigating and visualizing tortuous occluded vascular pathways defines the need to provide a device to assist in the navigation and visualization of vascular pathways.
Several intravascular devices have been described which purport to aid the advancement of guide wires and the like, and/or allow for the injection of fluids. Engleson U.S. Pat. No. 4,739,768 describes a single lumen device used to track a guide wire from an access site to an internal tissue along a tortuous path. The device can also be used to deliver an injectable fluid at a tissue site. Shockey et al U.S. Pat No. 5,120,323 describes a guide catheter system including two single lumen guide catheters. A working catheter can be passed through the inner catheter and fluids can be perfused between the inner catheter and the outer catheter. Kaltenbach U.S. Pat. No. 5,131,406 describes a guide which can be introduced into a narrow passage in a human body, such as into a narrow blood vessel in a human heart. Sharkawy U.S. Pat. No. 5,021,044 describes a multilumen vascular catheter for the delivery of therapeutic fluids to a patient's blood vessel.